The present invention relates in general to gas filters and more specifically to a disposable gas filter having an integral adhesive seal.
Gas filters, such as air filters, are normally mounted in an apparatus which draws or pushes the gas through the filter member. Eventually the filter member becomes clogged with the particular filtrate it is designed to capture and must be replaced. Accordingly, it is important to have a filter assembly which is easily positioned and removed, and assures secure positioning within the device in which it is mounted. Filters have been developed made out of a thin layer of relatively fragile filter material which may have cover layers of porous cover material. For such filters it is important that the mounting means takes into account both its non-rigid nature and its relatively delicate construction. Over the years, numerous systems have been developed for the mounting of gas filters, however, none have been developed which fully meet these needs.
For example, U.S. Pat. No. 4,426,214 to Vandrish, issued Jan. 17, 1984, describes a filter for use in a device for detecting particulate contaminants. This filter consists of a filter medium sandwiched between two pieces of plastic material having holes exposing the filter medium to the gaseous medium. The edges of plastic may be bonded to each other and the filter medium by a layer of adhesive. There is no method disclosed for the filter assembly to form a seal with the apparatus.
U.S. Pat. No. 2,557,279 to Greenberg, issued Jun. 19, 1951, describes vacuum cleaner filters. The filter consists of a bulky filter pad positioned in a shaping ring and a cover. The cover has two fabric disks permanently secured together along their edges for at least half of their diameter. The remaining other half of the diameter is connected by a slide fastener means. The filter assembly does not form a seal with its apparatus.
The patent to Whipple, U.S. Pat. No. 2,142,064, issued May 29, 1937, shows a filter assembly for use in a respirator. It similarly involves the use of an external frame means to hold a disc pad filter in place, subjecting the filter to damage and tears in assembling. Filter replacement requires the setting of the filter between various flanges and holding means.
U.S. Pat. No. 3,912,473 of Wilkins, issued Oct. 14, 1975, describes a vent filter. The filter is in the form of a bulky rigid pad. It is mounted in a circular housing. The :filter pad is loosely placed within the housing. There is no method to assure a seal of the filter to the apparatus.
U.S. Pat. No. 4,410,341 of Edwards, et al., issued on Oct. 18, 1983, describes a fluid filter cartridge. The filter consists of a pair of annular sheets of filter media that are sandwiched between a pair of mating halves and are separated by a ring member to engage each sheet of filter material against a respective one of the confronting halves.
U.S. Pat. No. 5,227,074 of Nichols et al., issued Jul. 13, 1993 discloses a filter for medical instrument sterilization containers. The filter material is positioned on a peripheral frame that is adapted to cooperate with an entry port. Several cross members span the aperture and form a frame on which the filter medium is positioned. There is no means for sealing the filter medium to the apparatus.